Discussion.—
The amplitude of the orbital contribution is extraordinary large if compared to that of the spin for nominally equal coupling constant \(\alpha \)  and a colossal Edelstein response is demonstrated. Although similar in structure to the SRE, the origin of the ORE does not rely on the atomic spin-orbit interaction, instead it is solely due to a finite momentum-dependent overlap between Wannier orbitals enabled by the broken mirror symmetry. For this reason the magnitude of the OR coupling is typically much larger [1]}, [2]}, [3]}, [4]}, [5]} than the corresponding one in the spin channel. These features open the possibility to both a wide amplitude tunability of the Edelstein effect and sign variation through a gate that changes the charge density and allows us to sweep the Fermi level around avoided crossings. An ideal platform is represented by 2D superconductors realized at LAO/STO (LaAlO\(_{3}\) /SrTiO\(_{3}\) ) interfaces [6]}, where an electric field has been shown to be effective in varying the electron density and tuning the chemical potential close to orbitally driven avoiding crossings [7]}. Furthermore, since the disclosed orbital Edelstein effect requires solely s-wave superconductivity, its application can be extended to ultrathin elemental superconductors as well as hybrid implementations through proximized superconductivity.
